Embedding nanoparticles in thermoplastic polymers

Abstract

The present invention relates to a polymeric material having one or more nanoparticles embedded within the surface layer of a single side of the material. In some embodiments, the nanoparticles are microbiocidal nanoparticles which impart antimicrobial characteristics to the polymeric material within which they sprayed and pushed by are embedded.

What is claimed is: 
     
       1. A polymeric material comprising:
 a first side and a second side; 
 a modified surface layer on the first side comprising a plurality of separated patches of microbiocidal nanoparticles embedded therein in a non-continuous distribution in which each patch is not in contact with other patches, the modified surface layer having a thickness less than or equal to a diameter of said nanoparticles; and 
 a bulk polymer extending between said modified surface layer and the second side, wherein the second side and the bulk polymer are free of the nanoparticles, 
 wherein the polymeric material has a thickness that is greater than the diameter of the nanoparticles, 
 wherein a penetration depth of at least some of the nanoparticles within the modified surface layer is about half of a shortest diameter of the nanoparticles, 
 wherein the polymeric material is a thermoplastic textile material, wherein the surface concentration of the nanoparticles is between 1-200 μg/cm 2 , and wherein the patches have an average separation of about 0.5-2 microns. 
 
     
     
       2. The polymeric material of  claim 1 , wherein the surface concentration of the nanoparticles is between 10-30 μg/cm 2 . 
     
     
       3. A polymeric material produced by a process comprising the steps of:
 providing a polymeric material having at a first side and a second side; 
 heating a surface layer of the first side to soften the surface layer at a depth sufficient to receive and embed nanoparticles in the surface layer; and 
 depositing microbiocidal nanoparticles comprising a microbiocidal agent onto the softened surface layer to immobilize the microbiocidal nanoparticles in the softened surface layer, to thereby form a modified surface layer having a plurality of separated patches of the microbiocidal nanoparticles embedded in the first surface in a non-continuous distribution in which each patch is not in contact with other patches; 
 wherein the patches have on average a separation of about 0.5 to 2 microns, wherein the modified surface layer has a thickness less than or equal to a diameter of said microbiocidal nanoparticles; 
 wherein the material further comprises a bulk of the polymeric material extending between said modified surface layer and the second side, wherein the bulk of, and the second side of, the polymeric material are free of the microbiocidal nanoparticles; and 
 wherein the polymeric material has a thickness that is greater than the diameter of the microbiocidal nanoparticles; 
 wherein a penetration depth of at least some of the microbiocidal nanoparticles within the modified surface layer is about half of a shortest diameter of the microbiocidal nanoparticles; and 
 wherein the polymeric material is a thermoplastic textile material. 
 
     
     
       4. The polymeric material of  claim 3 , wherein the surface layer is softened to a depth less than or equal to the diameter of the microbiocidal nanoparticles. 
     
     
       5. The polymeric material of  claim 4 , wherein said microbiocidal agent comprises a metal-based formulation. 
     
     
       6. The polymeric material of  claim 5 , wherein said metal-based formulation comprises TiO 2 , Ag 2 O, Ag—TiO 2 , or a combination thereof. 
     
     
       7. The polymeric material of  claim 6 , wherein said polymeric material comprises a thermoplastic polymer. 
     
     
       8. The polymeric material of  claim 7 , wherein said thermoplastic polymer comprises polyethylene terephthalate.